WaveWare Adaptive AlphaNet - Manual (Page 144)

Appendix E — Understanding message line positions (Top, Middle, Bottom, Fill)
144 5 — Appendix
Triple-line (7000 series) and AlphaVision ™ Full Matrix
Top/Bottom
These two positions work together. There is an imaginary line
between the top half and the bottom half of the display. We will call this
line the centerline. In the example below, the centerline is between the
Hello and the lots of text about basically. The centerline divides what is
used on the sign for top position commands from what is used for bottom.
Establishing the position of the centerline
The centerline position is typically established by the first top
command received and the rest of the space is used for the bottom. If the
bottom command comes first, the centerline is placed at its highest
possible position, row 8, allowing for one line of 7-dot characters on the
top. If the top command comes first, and not the bottom, the centerline’s
position is determined by the amount of text following the position
command.
Examples:
• If one 7-dot high line of text is received (following a top command),
the centerline will be fixed at row 8.
• If one line of 10-dot characters is received (following a top
command), the centerline will be placed at position 11.
• If two lines of 5-dot high characters are received (following a top
command), the centerline is placed at row 12 (5 for each line of text,
plus the 2 blank rows between the lines).
Two exceptions to the above rules are as follows:
• The centerline is never placed higher than 8 rows from the top of the
sign.
• The centerline is never placed lower than 8 rows from the bottom of
the sign. This ensures that there is always room for one line of 7-dot
high characters on the top or bottom (including one blank row).
Once its position is established, the centerline remains fixed at that
position until a Fill or Middle position command is received. All
subsequent top or bottom position commands use the amount of space set
by the position of the centerline. You cannot change the position of the
Centerline